1. Field of the Invention
The present invention relates to an air conditioner for a vehicle, and more particularly, to an air conditioner for a vehicle that is capable of easily and simply assembling a thermistor-holding device insertedly with a coupling hole formed at one side surface of a lower case of an air conditioning case, while inserting first and second protrusions formed through upper and lower molds around the coupling hole thereto, such that the total number of parts and the working period are all reduced to improve the productivity of the product and the repairing or exchanging work of the thermistor is carried out easily.
2. Background of the Related Art
In general, an air conditioning system of the air conditioner for a vehicle includes a compressor, a condenser, a receiver drier, an expansion valve, and an evaporator that are sequentially connected by a refrigerant pipe, such that as the compressor is activated by the power of an engine, refrigerant is circulated therein.
In such the air conditioning system, the refrigerant gas compressed to high temperature and pressure in the compressor is heat-exchanged with the ambient air surrounding the condenser, while being passed through the condenser, such that the refrigerant gas is changed into a liquid state. The liquefied refrigerant is decontaminated when passed through the receiver driver, and the decontaminated refrigerant is changed with low temperature gas after passing through the expansion valve. The low temperature gaseous refrigerant is heat-exchanged and cooled with the ambient air surrounding the evaporator while passing through the evaporator, and the cool air is discharged through a blower to the inside of the vehicle. Next, the low temperature gaseous refrigerant that is generated through the evaporator is transferred back to the compressor wherein the cycling of the refrigerant is repeated.
Under the above cycling process of the refrigerant, condensed water may be frozen by the difference between an evaporation temperature and an outside temperature, and in this case, the freezing is especially generated on the surface of the evaporator, which makes the heat-exchanging efficiency of the evaporator greatly deteriorated.
Thus, a thermistor as a temperature sensor is mounted at the front of the evaporator or inside the evaporator core, for sensing the temperature of cool air emitted from the evaporator, and if the sensed temperature falls to 0° C. below, the compressor stops so as not to work the air conditioning system. To the contrary, if the sensed temperature rises to 4° C. above, the compressor is activated again so as to work the air conditioning system, thereby preventing the evaporator from being frozen.
The thermistor is mounted by means of two types: one being mounted between tubes in such a manner as to be fixedly fit to radiant fins of the evaporator; and the other being mounted spaced apart from the evaporator by a predetermined distance.
As shown in FIGS. 1 and 2, a thermistor 180 is mounted by means of a thermistor-holding device 130 that is inserted between the radiant fins 113 of the evaporator 112. The thermistor-holding device 130 includes a loop-like locking part 171 formed at one end portion thereof, an insertion portion 173 formed at one side of the locking part 171 for inserting the thermistor 180 thereinto, and a plurality of hooks 174 formed extended long in a horizontal direction at the lower portion of the locking part 171 in such a manner as to be inserted between the radiant fins 113.
However, in the case where the thermistor 180 is mounted at the front of the evaporator 112 by using the thermistor-holding device 130, the plurality of hooks 174 of the thermistor-holding device 130 is inserted between the radiant fins 113 of the evaporator 112, such that if the insertion is carried out carelessly, the radiant fins 113 may be damaged or permanently deformed. Further, as the hooks 174 become weak at their supporting forces against the radiant fins 113 after the insertion into the radiant fins 113, the thermistor-holding device 130 may be moved undesirably by the wind pressure of air passing through the evaporator 112.
As a result, the thermistor-holding device 130 may be moved from its original position inserted into the radiant fins 113 or even escaped from the radiant fins 113, such that the thermistor 180 does not sense the cooling air temperature on the surface of the evaporator 112, thereby decreasing the performances of the air conditioning system and causing the generation of defective products.
Moreover, a wire 181 connected to the end portion of the thermistor 180 traverses the evaporator 112 in such a manner as to be loosely connected to the outside terminal of the air conditioning case 110, such that the wire 181 keeps the air being sent to the evaporator 112 from gently flowing. More particularly, in a case where the thermistor 180 is repaired or exchanged when it is out of order, the air conditioning case 110 is first disassembled before the thermistor 180 is separated from the evaporator 112, thereby making it difficult to carry out the repairing or exchanging work.
To solve the above-mentioned problems, there is disclosed in Korean Patent Publication No. 2004-0108581 filed by the applicant of the present invention. Referring to FIGS. 3 and 4 showing the another type of prior art, a thermistor-holding device 130 of an evaporator in an air conditioning case 110 includes: a coupling hole 120 formed on one side surface of an air conditioning case 110 divided into a pair of cases and having protrusions 111 formed along the inner periphery thereof; a protruded part 113 mounted at the outer surface of the air conditioning case 110 in such a manner as to be placed around the coupling hole 120; an assembling part 140 inserted along the inner periphery of the protruded part 113 in such a manner as to be coupled to the coupling hole 120; and a support part 142 coupled to the assembling part 140 in such a manner as to be inserted through the coupling hole 120 and disposed in a horizontal direction near the evaporator 112 mounted inside of the air conditioning case 110, for supporting the wire 181 connected at the end thereof with the thermistor 180.
After the thermistor-holding device 130 is fixedly mounted through the coupling hole 120 of the air conditioning case 110, the wire 181 is supported by means of the support part 142 coupled on the thermistor-holding device 130, such that the wire 181 and the thermistor 180 connected to the wire 181 are not moved or escaped from their original positions, thereby allowing the cooling temperature on the surface of the evaporator 112 to be accurately sensed. Also, in the case where the thermistor 180 needs to be repaired or exchanged when it is out of order, the thermistor 180 can be easily repaired or exchanged through the coupling hole 120 of the air conditioning case 110.
As the thermistor-holding device 130 has a relatively complicated structure, however, there occurs a problem that the number of parts and the working period are increased.
On the other hand, the structure wherein the protrusions 111 are formed on the inner periphery of the coupling hole 120 of the air conditioning case 110 and the thermistor 180 is assembled through the coupling hole 120 is applied to the air conditioning case 110 that is divided into left and right cases. Upon injection-molding for the air conditioning case 110, a parting line P of a mold is formed at a highest point of each protrusion 111 so as to form the protrusions 111 on the inner periphery of the coupling hole 120 of the air conditioning case 110, and the mold is separated left and right, such that the protrusions 111 are formed on the inner periphery of the coupling hole 120.
However, in the structure wherein the thermistor 180 is mounted through the coupling hole 120 formed on one side surface of a lower case in the air conditioning case 110 that are divided into an upper left case, an upper right case, and the lower case, the parting line P′ of the mold for injection-molding the air conditioning case 110 is formed on the lower portion of the air conditioning case 110, such that if the protrusions 111 are formed on the inner periphery of the coupling hole 120 of the air conditioning case 110, undesirably, undercut may occur on the protrusions 111.